Single radio switching between multiple wireless links

ABSTRACT

A computing device (such as a computer gaming console) uses only a single radio to concurrently communicate with a wireless network access point and wireless client devices such as game controllers or peripherals. To establish and maintain both a high-throughput link with the access point, and a low-latency link with the client device(s), the single Wi-Fi radio of the computing device is configured to periodically switch between a channel used for the high-throughput link and a different channel that is used for the low-latency link—thus implementing a combination of frequency division multiplexing (FDM) and time division multiplexing (TDM). The console may use aspects of the Wi-Fi protocol standard to ensure that periodically switching its single radio between the two channels is accomplished while maintaining reliable communication on both channels.

RELATED APPLICATIONS

This application is related to the following U.S. applications filed onor about the same day as the present application Ser. No. 15/149,109,entitled “SINGLE RADIO SERVING MULTIPLE WIRELESS LINKS”, filed on orabout the same day as the present application, the contents of which areincorporated herein by reference in its entirety for all purposes.

BACKGROUND

Wireless communication may be used as a means of accessing a network.Wireless communication has certain advantages over wired communicationsfor accessing a network. One of those advantages is a lower cost ofinfrastructure to provide access to many separate locations or addressescompared to wired communications. This is the so-called “last mile” or“last meter” problem. Another advantage is mobility. Wirelesscommunication devices, such as cell phones, printers, and accessories(e.g., keyboards, mice, remote controls, video game controller) are nottied by wires to a fixed location.

To facilitate wireless communications, various organizations andindustry groups have promulgated a number of wireless standards. Theseinclude the IEEE 802.11 (Wi-Fi) standards, and Wi-Fi Direct (WFD). Allof these standards may include specifications for various aspects ofwireless communication with a network. These aspects include processesfor registering on the network, carrier modulation, frequency bands ofoperation, and message formats.

SUMMARY

Examples discussed herein relate to configuring a device with a singlewireless interface radio to establish and maintain, at the same time,both a high-throughput (e.g., Wi-Fi) connection and a low-latency (i.e.,latency optimized) connection. A wireless interface radio is configuredto communicate with an access node (e.g., Wi-Fi router) using a firstfrequency band and a first series of time allocations. The wirelessinterface radio is also configured to communicate with at least oneclient device (e.g., game controller) using a second frequency band anda second series of time allocations. The first series of timeallocations and the second series of time allocations arenon-overlapping. Thus, the communication by the wireless interface radiois both frequency division multiplexed (FDM) and time divisionmultiplexed (TDM). Information is sent to at least one client device viathe second frequency band. This information is to be used by at leastone client device to select a time to transmit using the secondfrequency band. Based on a transmission received via the wirelessinterface radio, a first duration of a first time allocation of at leastone of the first series of time allocations and the second series oftime allocations is altered. This allows the wireless interface radio toextend (or shorten) the period it is listening on a particular frequencyband in order to allow the transmission to complete.

In an example, a high-throughput link is configured that uses a wirelessinterface radio to communicate with an access node using a firstfrequency band and a first series of time allocations. A low-latencylink is also configured that uses the wireless interface radio tocommunicate with at least one client device using a second frequencyband and a second series of time allocations. Since the first series oftime allocations and the second series of time allocations arenon-overlapping, the two links are a combination of time and frequencymultiplexed. A time indicator is sent to a client device that iscommunicating via the second frequency band. Responsive to this timeindicator, the client device selects a time to transmit that is during aone of the second series of time allocations.

In an example, a low-latency link between a client device and a softaccess point is configured. This low-latency link uses a first frequencyband and a first series of time allocations. The access pointcommunicates with a wireless network access node (e.g., wireless routerconnected to the Internet) using a second frequency band and a secondseries of time allocations. The first series of time allocations and thesecond series of time allocations are non-overlapping. A time indicatoris received from the access point via the low-latency link. Responsiveto this time indicator, the client device is configured to select atransmit time that is during a one of the first series of timeallocations.

In an example, a first wireless interface link to communicate with anaccess node using a first channel of a frequency band is established. Asecond wireless interface link to communicate with a client device usinga second channel of the frequency band is also established. Via thefirst wireless interface link, a first message to the access nodeindicating the first wireless interface link is to enter a first dormantstate is sent. Data is concurrently received from the access node usingthe first channel and the client device using the second channel bydemodulating a wide channel comprising the first channel and the secondchannel. The concurrently received data including an indicator that theaccess node has received the first message indicating the first wirelessinterface link is to enter the first dormant state.

In an example, a low-latency link between the client device and a softaccess point device is configured. The low-latency link is configured touse a first frequency band and a first series of time allocations. Thesoft access point device is to communicate with a network access nodeusing a second frequency band and a second series of time allocations.The first series of time allocations and the second series of timeallocations are to be non-overlapping. Via the low-latency link, a firstmessage is transmitted to the soft access point using the firstfrequency band during a first one of the first series of timeallocations. In response to not receiving, via the first frequency band,a first acknowledgement associated with the first message, a first retryof the first message is sent to the soft access point using the secondfrequency band during the first one of the first series of timeallocations. In response to receiving, via the second frequency band, asecond acknowledgment associated with the first retry of the firstmessage, a second message is sent to the soft access point using thesecond frequency band during the first one the first series of timeallocations.

In an example, a wireless interface radio is configured to communicatewith a first access node using a first frequency band and a first seriesof time allocations. The wireless interface radio is also configured tocommunicate with at least one client device using a second frequencyband and a second series of time allocations. The first series of timeallocations and the second series of time allocations arenon-overlapping. With the access node, a first wireless communicationlink associated with first media access control (MAC) identifier isestablished. With the access node, a second wireless communication linkassociated with a second MAC identifier is established. Informationassociated with the second MAC identifier is transmitted to constrain atiming that the access node will use for at least one transmission bythe access node.

In an example, a wireless interface radio is configured to communicatewith a first access node using a first frequency band and a first seriesof time allocations. The wireless interface radio is also configured tocommunicate with at least one client device using a second frequencyband and a second series of time allocations. The first series of timeallocations and the second series of time allocations arenon-overlapping. A first wireless communication link associated withfirst media access control (MAC) identifier is established with theaccess node. Information associated with a second MAC identifier istransmitted to constrain a timing that the access node will schedule atleast one transmission by the access node. The second MAC identifier isnot associated with a wireless communication link with the access node.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Furthermore,the claimed subject matter is not limited to implementations that solveany or all disadvantages noted in any part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which the above-recited and otheradvantages and features can be obtained, a more particular descriptionis set forth and will be rendered by reference to specific examplesthereof which are illustrated in the appended drawings. Understandingthat these drawings depict only typical examples and are not thereforeto be considered to be limiting of its scope, implementations will bedescribed and explained with additional specificity and detail throughthe use of the accompanying drawings.

FIG. 1 is a block diagram illustrating a communication system.

FIG. 2 is a flowchart illustrating a method of operating a communicationsystem.

FIG. 3 is a diagram illustrating dynamic FDM-TDM channel switching.

FIG. 4A is a diagram illustrating an extended stay on a high-throughputchannel.

FIG. 4B is a diagram illustrating an extended stay on a low-latencychannel.

FIG. 5 is a flowchart illustrating a method of scheduling a transmissionby a client device.

FIG. 6 is a diagram illustrating a scheduled transmission.

FIG. 7 is a block diagram illustrating a multi-channel single radioWi-Fi communication system.

FIG. 8 is a flowchart illustrating a method for setting a transmissiontime by a client device.

FIG. 9 is a diagram illustrating multi-channel reception by a singleradio.

FIG. 10 is a diagram illustrating multi-channel reception to preventholdover.

FIG. 11 is a diagram illustrating multi-channel transmission.

FIG. 12 is a diagram illustrating client device following.

FIG. 13 is a diagram that illustrates setting an access nodetransmission time.

FIG. 14 is a diagram that illustrates setting a broadcast/multicasttransmission time.

FIG. 15 is a diagram illustrating time allocations to receive beacontransmissions.

FIG. 16 is a diagram illustrating an aggregated frame transmission.

FIG. 17 is a flowchart illustrating a method of operating acommunication system.

FIG. 18 is a flowchart illustrating a method of operating a clientdevice.

FIG. 19 is a flowchart illustrating a method of using a connectedvirtual client to constrain access point transmission timing.

FIG. 20 is a flowchart illustrating a method of using a non-connectedvirtual client to constrain access point transmission timing.

FIG. 21 is a block diagram of an example device with wirelesscapability.

FIG. 22 is a block diagram of an example computer system.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Examples are discussed in detail below. While specific implementationsare discussed, it should be understood that this is done forillustration purposes only. A person skilled in the relevant art willrecognize that other components and configurations may be used withoutparting from the spirit and scope of the subject matter of thisdisclosure. The implementations may include a machine-implementedmethod, a computing device, a state-machine implemented method, orwireless network device.

In an embodiment, a computing device (such as a computer gaming console,tablet PC, set-top box, smartphone, wireless enabled television, etc.)uses only a single radio to concurrently communicate with a wirelessnetwork access point and wireless client devices. For example, a gameconsole may use a single radio to communicate with a Wi-Fi router andwith game controllers. Typically, communication with the Wi-Fi router isdesired to have high-throughput while communication with the gamecontrollers is desired to have low-latency.

To establish and maintain both a high-throughput link with the Wi-Fiaccess point, and a low-latency link with the wireless gamecontroller(s), the single Wi-Fi radio of the computing device isconfigured to periodically switch between a channel used for thehigh-throughput link and a different channel that is used for thelow-latency link—thus implementing a combination of frequency divisionmultiplexing (FDM) and time division multiplexing (TDM). However,because (at least) the access point used for the high-throughput link isunaware that the computing device is periodically switching channels,the computing device (and/or clients of the computing device's softaccess point) may deviate from strict time-based channel switching inorder to maintain reliable communication. In addition, the computingdevice may use aspects of the Wi-Fi protocol standard to ensure thatperiodically switching its single radio between the two channels isaccomplished while maintaining reliable communication on both channels.

For example, one issue that can occur is when the wireless networkaccess point for the high-throughput link is sending (and computingdevice is receiving) a beacon frame when the time for a channelswitchover occurs. If the channel switchover were to occur on schedule,at least part of the information in the beacon frame would be missed. Inan embodiment, the computing device postpones switching between channelsin order to complete the reception of the beacon frame. The computingdevice may then shorten the time spent on the low-latency channel duringa subsequent period that is allocated to the low-latency channel. Thisadjustment can be used to maintain an average period for cycling betweenchannels, and/or maintain a sleep/wake schedule synchronization withclient devices on the low-latency link.

In another example, a client device starts to transmit on thelow-latency link a short time before a channel switchover is to occur.Again, if the channel switchover were to occur on schedule, at leastpart of the information being transmitted by the client device would bemissed. In an embodiment, if a transmission by a client device isdetected close to the channel switching time, the computing device canpostpone switching between channels in order to completely receive thetransmission from the client device. The computing device may thenshorten the time spent on the high-throughput channel during asubsequent period allocated to the high-throughput channel. Thisadjustment can be used to maintain an average period for cycling betweenchannels, and/or maintain a sleep/wake schedule synchronization withclient devices on the low-latency link.

In another example, the relative time spent on the high-throughputchannel versus the low-latency channel may be varied according to thetraffic on one or both of the channels. In this manner, throughput onthe high-throughput channel and latency on the low-latency channel canbe optimized according to the activity on the channels.

In another example, the computing device can send scheduling and/orcontrol information to its client devices via the low-latency links.This information can be used to prevent, or help prevent, attempts bythe client devices on the low-latency link from trying to transmit whilethe computing device is configured to listen to only the high-throughputchannel. For example, the computing device may send a recommended sleepduration to a client device. This sleep duration can be selected suchthat the client device will (or is likely to) remain asleep while thecomputing device is configured to listen to the high-throughput channel.

In another example, to prevent transmissions by the wireless networkaccess point to the computing device via the high-throughput channelwhile the computing device is operating on the low-latency channel, thecomputing device can indicate (e.g., in a NULL frame on thehigh-throughput channel) to the wireless network access point that it isgoing to sleep. If, for some reason, the wireless network access pointdoes not respond to this message (e.g., with an ACK frame), thecomputing device may switch into a mode whereby the computing device canmonitor the high-throughput channel for an acknowledgement whilesimultaneously listening for traffic from client devices on thelow-latency channel.

In another example, if the wireless network access point has notacknowledged that the computing device is going to sleep, and thecomputing device wants to transmit on the low-latency link (as opposedto just listening), the computing device can send a transmission on thehigh-throughput channel that appears to be from a device that is notconnected to the wireless network access point. This transmission canindicate a transmission duration that corresponds to the time thecomputing device needs to transmit on the low-latency link. In thismanner, the Wi-Fi inter-network/intra-channel collision avoidancealgorithm used by the wireless network access point will prevent thewireless network access point from transmitting to the computing device(or any other Wi-Fi device.) After the computing device has completedits transmission on the low-latency link, the computing device canswitch into the aforementioned mode whereby the computing device canmonitor the high-throughput channel for an acknowledgement whilesimultaneously listening for traffic on the low-latency channel.

In another example, when it is time for the computing device to switchits single radio from the high-throughput channel to the low-latencychannel (i.e., an FDM-TDM channel switch), the wireless network accessnode may be sending a beacon frame. Likewise, relatively close to thestart of a beacon frame transmission, the computing device may have sentan indicator (e.g., in a NULL frame on the high-throughput channel) tothe wireless network access point that the computing device is going tosleep. However, because the wireless network access point is sending, orabout to send, a beacon frame, the wireless network access point deferssending an acknowledgement that the computing device is going to sleep.To prevent these cases from occurring, the computing device can adjustthe time allocations spent on the high-throughput channel such that thebeacon frame transmissions occur while the computing device is operatingon the high-throughput channel.

In another example, when it is time for the computing device to switchits single radio from the high-throughput channel to the low-latencychannel (i.e., an FDM-TDM channel switch), the wireless network accessnode may be sending broadcast or multicast frames. Since the wirelessnetwork access node is busy sending these frames, the computing devicemay not be able to send an indicator to the wireless network accesspoint that it is going to sleep and/or receive an acknowledgement. Toprevent this from occurring, the computing device can send transmissionson the high-throughput channel that appears to be from a device that isconnected to the wireless network access point, but that is notidentified (e.g., by MAC address) as being the computing device (i.e., a‘virtual’ client). These transmissions indicate to the wireless networkaccess point that the virtual client device will be sleeping at alltimes except those close to the beacon time. Since broadcast/multicastframes are sent at times when all of the clients are awake, the wirelessnetwork access point will be constrained to schedule broadcast/multicastframes close to the beacon time when the virtual client device appearsto wireless network access node to be awake.

In another example, when it is time for the computing device to switchits single radio from the high-throughput channel to the low-latencychannel (i.e., for a FDM-TDM channel switch), the wireless networkaccess node may be sending aggregated frames to another client (i.e.,not the computing device). Since the wireless network access node isbusy sending these frames, the computing device may not be able to sendan indicator to the wireless network access point that the computingdevice is going to sleep and/or receive an acknowledgement. When thisoccurs, the computing device may elect to continue to switch channelsaccording to the FDM-TDM time allocations without informing the wirelessnetwork access point that the computing device is going to sleep. Bycontinuing to switch without informing the wireless network access node,the computing device may switch away and then back to thehigh-throughput channel before the aggregated frame transmissioncompletes. By returning to the high-throughput channel before the frametransmission completes, it is unlikely that the computing device willmiss a transmission from the wireless network access point, ordisconnect the link with the computing device.

FIG. 1 is a block diagram illustrating a communication system. In FIG.1, communication system 100 comprises wireless network access node 110,network 120, client device 130, and computing device 150. Computingdevice 150 includes radio 151. Wireless network access node 110 isoperatively coupled to network 120. Wireless network access node 110 isoperatively coupled to computing device 150 by wireless link 141. Clientdevice 130 is operatively coupled to computing device 150 by wirelesslink 142.

Wireless network access node 110 is a network element capable ofproviding wireless communication to wireless capable devices (e.g.,computing device 150.) Wireless network access node 110 can be, forexample, one or more of a Wi-Fi access node, a Wi-Fi hotspot, a Wi-Figateway, a base transceiver station, a radio base station, an eNodeBdevice, or an enhanced eNodeB device. Wireless network access node 110is connected to network 120. Example devices that may be, comprise,and/or include wireless network access node 110 include, but are notlimited to, example wireless capable device 2100 (described herein withreference to FIG. 21) and/or example computer system 2200 (describedherein with reference to FIG. 22).

Network 120 is a wide area communication network that can provide wiredand/or wireless communication to wireless network access node 110.Network 120 and can comprise wired and/or wireless communicationnetworks that include processing nodes, routers, gateways, physicaland/or wireless data links for carrying data among various networkelements, including combinations thereof, and can include a local areanetwork, a wide area network, and an internetwork (including theInternet). Network 120 can also comprise wireless networks, includingbase station, wireless communication nodes, telephony switches, internetrouters, network gateways, computer systems, communication links, orsome other type of communication equipment, and combinations thereof.Wired network protocols that may be utilized by network 120 compriseEthernet, Fast Ethernet, Gigabit Ethernet, Local Talk (such as CarrierSense Multiple Access with Collision Avoidance), Token Ring, FiberDistributed Data Interface (FDDI), and Asynchronous Transfer Mode (ATM).Links between elements of network 120, can be, for example, twisted paircable, coaxial cable or fiber optic cable, or combinations thereof.Wireless network protocols that may be utilized by communication system100 may comprise one or more IEEE 802 specified protocols.

Other network elements may be present in network 120 to facilitatecommunication with wireless network access node 110 but are omitted forclarity, such as base stations, base station controllers, gateways,mobile switching centers, dispatch application processors, and locationregisters such as a home location register or visitor location register.Furthermore, other network elements may be present to facilitatecommunication between among elements of communication system 100 whichare omitted for clarity, including additional computing devices, clientdevices, access nodes, routers, gateways, and physical and/or wirelessdata links for carrying data among the various network elements.

In an embodiment, computing device 150 may be any device, system,combination of devices, or other such communication platform capable ofcommunicating wirelessly with wireless network access node 110 andwirelessly with client device 130. Computing device 150 can operateusing a single wireless interface radio 151 to establish wireless links141 and 142 and communicate concurrently with wireless network accessnode 110 and client device 130, respectively. Computing device 150 mayconnect to wireless network access node 110 as a client of a wirelessnetwork (e.g., a wireless network associated with a single BSSID)provided by wireless network access node 110. Client device 130 mayconnect to a wireless network provided by computing device 150. Thewireless network provided by computing device 150 may be a peer-to-peertype wireless network. Computing device 150 may be known as the ‘softaccess point’ or ‘soft-AP’ for the network computing device 150 providesto client device 130 via wireless link 142. Example devices that may be,comprise, and/or include computing device 150 include, but are notlimited to, example wireless capable device 2100 (described herein withreference to FIG. 21) and/or example computer system 2200 (describedherein with reference to FIG. 22).

Client device 130 may be, for example, a video game controller, computerperipheral (e.g., mouse, keyboard, printer, speakers), a mobile phone, awireless phone, a wireless modem, a personal digital assistant (PDA), avoice over internet protocol (VoIP) phone, a voice over packet (VOP)phone, or a soft phone, as well as other types of devices or systemsthat can exchange data with computing device 150 via wireless link 142.Other types of communication platforms are possible. Example devicesthat may be, comprise, and/or include client device 130 include, but arenot limited to, example wireless capable device 2100 (described hereinwith reference to FIG. 21) and/or example computer system 2200(described herein with reference to FIG. 22).

In an embodiment, computing device 150 controls and/or configures radio151 to implement a combination of frequency division multiplexing (FDM)and time division multiplexing (TDM) for the communication via wirelesslink 141 and wireless link 142. In other words, radio 151 both switchesbetween at least two frequency bands (i.e., channels) to implementfrequency division multiplexing, and also communicates on a respectivefrequency band during a respective series of non-overlapping timeallocations to implement time division multiplexing. Thus, radio 151 mayperiodically communicate with wireless network access node 110 duringselected time periods using a first channel, and communicate with clientdevice 130 using wireless link 142 using a second channel during therest of the time. In an embodiment, the time periods are selected suchthat wireless link 141 is configured as a high-throughput link andwireless link 142 is configured as a low-latency link. In anotherembodiment, the time periods are selected such that wireless link 142 isconfigured as a high-throughput link and wireless link 141 is configuredas a low-latency link.

Wireless network access node 110 may be unaware that computing device150 is using FDM-TDM channel switching to communicate via wireless links141 and 142 using a single radio 151. Accordingly, wireless networkaccess node 110 may function under an assumption that wireless link 141is always on the same channel and is conforming to the protocolassociated with the wireless network type being provided by wirelessnetwork access node 110.

In an embodiment, computing device 150 may control radio 151 to deviatefrom strict fixed time channel switching in order to maintain reliablecommunication with both client device 130 and/or wireless network accessnode 110. In typical operation, computing device 150 communicatesalternately with wireless network access node 110 via link 141 and withclient device 130 via link 142. When communicating with wireless networkaccess node 110, radio 151 uses a first channel. When communicating withclient device 130, radio 151 uses a second channel. At nominally fixedintervals (i.e., TDM), radio 151 is switched between the first channeland the second channel (i.e., FDM)

Wireless network access node 110 may be sending (or will be unable tocomplete) a beacon frame when a time for FDM-TDM channel switch fromlink 141 to link 142 occurs. If the switchover of radio 151 from link141 to link 142 were to occur at that predetermined time, at least partof the information in the beacon frame would be missed by computingdevice 150. In an embodiment, computing device 150 does not switchbetween channels at the predetermined time and instead delays the switchin order to complete the reception of the beacon frame from wirelessnetwork access node 110. Computing device 150 may delay the FDM-TDMchannel switch by a predetermined amount of time (e.g., several ofmilliseconds) that allows for the complete reception of any beacon framewhich would not complete before the time nominally scheduled for theFDM-TDM channel switch.

After a FDM-TDM channel switch from link 141 to 142 is delayed to allowreception of the beacon frame to complete, computing device 150 may thenshorten the next (or any subsequent) time spent on link 141. Thisadjustment can be used to maintain an average (or nominal) period forcycling between links 141 and 142. This adjustment can also be used tohelp maintain a sleep/wake schedule synchronization with client device130 and link 142.

Client device 130 may be sending (or will be unable to complete) atransmission when a time for a FDM-TDM channel switch from link 142 tolink 141 occurs. If the switchover of radio 151 from link 142 to link141 were to occur at that predetermined time, at least part of theinformation transmitted by client device 130 could be missed bycomputing device 150. In an embodiment, computing device 150 does notswitch between channels at the predetermined time and instead delays theswitch in order to complete the reception of the transmission fromclient device 130. Computing device 150 may delay the FDM-TDM channelswitch by a predetermined amount of time (e.g., several of milliseconds)that allows for the complete reception of any client device 130transmission which would not complete before the time nominallyscheduled for the FDM-TDM channel switch.

After a FDM-TDM channel switch from link 142 to 141 is delayed to allowreception of the beacon frame to complete, computing device 150 may thenshorten the next (or any subsequent) time spent on link 141. Thisadjustment can be used to maintain an average (or nominal) period forcycling between links 141 and 142. This adjustment can also be used tohelp maintain a sleep/wake schedule synchronization with client device130 and link 142.

In an embodiment, the relative time spent communicating via link 141versus the time spent communicating via link 141 can be varied bycomputing device 150 according to the traffic on one or both of thechannels. In another embodiment, the relative time spent communicatingvia link 141 versus the time spent communicating via link 141 be canvaried by computing device 150 based on one or more of: an applicationbeing run on computing device 150, a device classification of clientdevice 130 (e.g., mouse vs. keyboard vs. game controller, etc.) In thismanner, throughput on link 141 and latency on link 142 can be optimizedaccording to the activity on the channels and/or expected needs of anapplications and/or client device. Likewise, throughput on link 142 andlatency on link 141 can be optimized according to the activity on thechannels and/or expected needs of an applications and/or client device.

In an embodiment, computing device 150 sends scheduling and/or controlinformation to client device 130 via link 142. This information can beused to prevent, or help prevent, attempts by client device 130 totransmit while radio 151 is configured to listen to only link 141. Forexample, computing device 150 may send a recommended sleep duration toclient device 130. This sleep duration can be selected by computingdevice 150 such that client device 130 will (or is likely to) remainasleep during period(s) of time when radio 151 is configured to listenon link 141.

As described herein, computing device 150 regularly spends at least sometime with radio 151 configured to communicate via link 142. When radio151 is configured to communicate via link 142, it cannot communicate vialink 141. In an embodiment, before performing a FDM-TDM channel switchfrom link 141 to link 142, computing device 150 sends an indicator towireless network access node 110. This indicator informs wirelessnetwork access node 110 that, as far as link 141 is concerned, computingdevice 150 is going to sleep and will not be receiving communication vialink 141. Wireless network access node 110 confirms receipt of thisindicator by sending computing device 150 an acknowledgement message vialink 141. When computing device 150 receives the acknowledgement messagevia link 141, computing device 150 may perform a FDM-TDM channel switchto link 142 (or go to sleep.)

Wireless network access node 110 may not respond to the ‘going to sleep’indicator before the predetermined time for the FDM-TDM channel switchfrom link 141 to link 142. This lack of response may occur becausewireless network access node 110 is busy with other traffic (e.g.,sending a beacon frame) or interference (e.g., traffic on anotherwireless network operating on the same or nearby channels.) Computingdevice 150 may then monitor link 141 and link 142 simultaneously.Computing device 150 may monitor link 141 in order to receive theacknowledgement message. Computing device 150 may monitor link 142 inorder to receive transmissions from client device 130 and respond tothese transmissions with a limited maximum latency time period.Computing device 150 may monitor both link 141 and 142 by receiving anddemodulating communication on both the channel used by link 141 and thechannel used by link 142. For example, if both link 141 and 142 useorthogonal frequency division multiplexing (OFDM), Computing device 150may monitor both link 141 and 142 by receiving at least the OFDMcarriers associated with link 141 and link 142, discarding datacorresponding to OFDM carriers not used by links 141 and 142, and thenseparately (i.e., by link or channel) processing the data associatedwith the respective OFDM carriers associated with each link 141 and 142.In an embodiment, appropriate filters and/or filter banks may be usedfor performing the desired separation.

Computing device 150 may have data to transmit to client device 130 whenwireless network access node 110 has not responded to the ‘going tosleep’ indicator before a predetermined time for a FDM-TDM channelswitch from link 141 to link 142. To prevent wireless network accessnode 110 from transmitting on link 141 while computing device 150 istransmitting data to client device 130 after the channel switch to link142, computing device 150 can send a transmission on the same channel aslink 141. This transmission is sent such that the transmission appearsto be from a device that is not connected to wireless network accessnode 110. This transmission can indicate a transmission duration thatcorresponds to the time the computing device needs to transmit on link142. In this manner, a collision avoidance algorithm used by wirelessnetwork access node 110 can prevent the wireless network access node 110from transmitting via link 142 for the specified transmission duration.After the computing device 150 has completed its transmission on link142, computing device 150 can switch into the aforementioned modewhereby computing device 150 can monitor link 141 for an acknowledgementwhile simultaneously listening for traffic on link 142.

To prevent (or help prevent) cases where wireless network access node110 is delayed from sending an acknowledgment due to a beacon frametransmission (or impending beacon frame transmission), computing device150 can adjust the time allocations (and/or timing of the FDM-TDMchannel switches) spent on link 141 and link 142 such that the beaconframe transmissions occur while radio 151 is known to be (or very likelyto be) configured to be on link 141.

Broadcast or multicast frames being sent by wireless network access node110 may also cause computing device 150 and/or wireless network accessnode 110 from communicating or responding to a ‘going to sleep’ message.Computing device 150 can send a transmission on the high-throughputchannel that appears to be from a device that is connected to thewireless network access node 110, but where that device is not computingdevice 150 (i.e., a ‘virtual’ client of wireless network access node 110created by computing device 150 for this purpose.) This transmission canindicate to wireless network access node 110 that the virtual clientdevice will be sleeping at all times except those close to the beacontime. Since broadcast/multicast frames are sent at times when all of theclients of wireless network access node 110 are awake, wireless networkaccess node 110 will be constrained to schedule broadcast/multicastframes close to the beacon time. This at least limits the effect ofbroadcast/multicast frames to switchover times that are close to thebeacon time.

Aggregated frames being sent by wireless network access node 110 mayalso cause computing device 150 and/or wireless network access node 110from communicating or responding to a ‘going to sleep’ message. Sincewireless network access node 110 is busy sending these aggregatedframes, computing device 150 may not be able to send the ‘going tosleep’ indicator to wireless network access node 110 and/or receive anacknowledgement. When this occurs, computing device 150 may elect tocontinue to switch between links 141 and 142 according to the FDM-TDMtime allocations without informing wireless network access node 110 thatit is going to sleep. By continuing to switch without informing wirelessnetwork access node 110, computing device 150 may switch away from link141 to link 142 and then back to link 141 before the aggregated frametransmission completes. By returning to link 141 before the frametransmission completes, computing device 150 may not miss a transmissionfrom wireless network access node 110, or need to re-establish link 141.

FIG. 2 is a flowchart illustrating a method of operating a communicationsystem. The steps illustrated in FIG. 2 may be performed by one or moreelements of communication system 100. A wireless interface radio isconfigured to communicate with an access node using a first frequencyband and a first series of time allocations (202). For example, radio151 may be periodically (and repetitively) configured and reconfiguredby computing device 150 to communicate with wireless network access node110 using a first wireless channel (i.e., frequency band—such as Wi-Fichannel 1) and a first series of time allocations (e.g., the first 4 msof an 8 ms cycle).

The wireless interface radio is configured to communicate with at leastone client device using a second frequency band and a second series oftime allocations (204). For example, radio 151 may be periodically (andrepetitively) configured and reconfigured by computing device 150 tocommunicate with client device 130 using a second wireless channel(i.e., frequency band—such as Wi-Fi channel 6) and a second series oftime allocations (e.g., the second 4 ms of an 8 ms cycle).

Via the second frequency band, and to the at least one client device,information to be used by the at least one client device to select atime to transmit using the second frequency band is sent (206). Forexample, computing device 150 may send, via the second frequency bandand to client device 130, an indicator of a recommended (or commanded)sleep duration and/or wakeup time. When the recommended time arrives,client device 130 may wakeup and transmit to computing device 150 usinglink 142. Computing device 150 may select the indicator of a recommended(or commanded) sleep duration and/or wakeup time such that radio 151will be tuned to the second frequency band when client device 130 wakesup.

Based on a transmission received via the wireless interface radio, afirst duration of a first time allocation of at least of the firstseries of time allocations and the second series of time allocations isaltered (208). For example, based on a transmission on link 142 fromclient device 130, computing device 150 may delay (i.e., postpone) theFDM-TDM channel switching of channels from a predetermined time to alater time. The amount of delay/postponement may be a predeterminedduration.

In a particular example, when computing device 150 determines that atransmission on link 142 from client device 130 is unlikely to, or willnot, complete before the predetermined time for the FDM-TDM channelswitch, computing device 150 may extend the time radio 151 listens tolink 142 this cycle. Likewise, when computing device 150 determines thata transmission (e.g., regular traffic, beacon frame, multicast frame,and/or aggregated frame) on link 141 from wireless network access node110 is unlikely to, or will not, complete before the predetermined time,computing device 150 may extend the time radio 151 listens to link 142this cycle. Responsive to extending a stay on one of the frequencybands, computing device 150 may shorten a subsequent (e.g., next) stayon the other frequency band. This second altered time allocation may beshortened by the amount that the first time allocation was lengthened.By extending a first time allocation for one frequency band, andshortening a second time allocation for the other frequency band, theoverall cycle time between the two bands can be maintained at a desiredaverage or mean cycle time. This can help keep the transmissions and/orwake-up times of client device 130 synchronized with computing device150.

FIG. 3 is a diagram illustrating dynamic FDM-TDM channel switching. InFIG. 3, the horizontal axis represents time, and the vertical axisrepresents frequency. A first frequency band, or channel, (f1) is shownabove the horizontal axis. A second frequency band (f2) is shown belowthe horizontal axis. The first frequency band is configured to be ahigh-throughput link and is therefore denoted HT in FIG. 3. This firstfrequency band can correspond to link 141 between computing device 150and wireless network access node 110. In another embodiment, this firstfrequency band can correspond to link 142 between computing device 150and client device 130. The second frequency band is configured to be alow-latency link and is therefore denoted LL in FIG. 3. This secondfrequency band can correspond to link 142 between computing device 150and client device 130. In another embodiment, this second frequency bandcan correspond to link 141 between computing device 150 and wirelessnetwork access node 110.

Typical (or nominal) FDM-TDM channel switching cycles are shown byFDM-TDM allocations 310, 311, 320, and 321. FDM-TDM allocations 310 and311 are illustrated as being on the f1 frequency band and are ofduration t_(a0). FDM-TDM allocations 320 and 321 are illustrated asbeing on the f2 frequency band and are of duration t_(b0). Thus, as canbe seen from allocations 310 and 320 in FIG. 3, a FDM-TDM cycle isnominally t_(cyc)=t_(a0)+_(b0) in duration. It can also be seen fromallocations 310, 311, 320, and 321 that the times that allocations 310and 311 are active on the first frequency band do not overlap the timesthat allocations 320 and 321 are active on the second frequency band.Thus, allocations 310, 311, 320, and 321 effect a multiplexing schemethat implements a combination of non-overlapping FDM and non-overlappingTDM.

FIG. 3 also illustrates extended allocation 312 and shortened allocation322. Extended allocation 312 and/or shortened allocation 322 may be theresult of an extended stay (i.e., postponed FDM-TDM channel switchingtime) by computing device 150 on the f1 frequency band. FDM-TDMallocation 312 is illustrated as being on the f1 frequency band for aduration t_(a1)+t_(a0)+t₁. Dashed line 322 illustrates the nominalswitching time (i.e., without allocation 312 being extended and/orallocation 322 being shortened) between allocation 312 and 322. FDM-TDMallocation 322 is illustrated as being on the f2 frequency band for aduration t_(b1)=t_(b0)+t₁. Thus, as can be seen from allocations 312 and322 in FIG. 3, the FDM-TDM cycle encompassing allocations 312 and 322 isnominally t_(cyc)=t_(a0)+t_(b0) in duration.

FIG. 3 also illustrates shortened allocation 313 and extended allocation323. Shortened allocation 313 and/or extended allocation 323 may be theresult of a shortened stay by computing device 150 on the f1 frequencyband. FDM-TDM allocation 313 is illustrated as being on the f1 frequencyband for a duration t_(b2)=t_(b0)+t₂. Dashed line 333 illustrates thenominal switching time (i.e., without allocation 313 being shortenedand/or allocation 323 being lengthened) between allocation 313 and 323.FDM-TDM allocation 322 is illustrated as being on the f2 frequency bandfor a duration t_(b2)=t_(b0)+t₂. Thus, as can be seen from allocations313 and 323 in FIG. 3, the FDM-TDM cycle encompassing allocations 313and 323 is nominally t_(cyc)=t_(a0)+t_(b0) in duration. In anembodiment, t₁ may be a predetermined amount of time. In anotherembodiment, t₁ may be dynamically adjusted by computing device 150. Thedynamic adjustments made to t₁ may be based on factors such as the typeof transmission that caused a postponement to a FDM-TDM channelswitching cycle, traffic on the current (or next) channel, anapplication being run on computing device 150, a device classificationof client device 130 (e.g., mouse vs. keyboard vs. game controller,etc.), or other factors that contribute to the performance (e.g.,latency and/or throughput) of communication system 100, and links 141and 142, in particular.

FIG. 4A is a diagram illustrating an extended stay on a high-throughputchannel. In FIG. 4A, the horizontal axis represents time, and thevertical axis represents frequency. A first frequency band, or channel(f1) is shown above the horizontal axis. A second frequency band (f2) isshown below the horizontal axis. The first frequency band is configuredto be a high-throughput link and is therefore denoted HT in FIG. 4A.This first frequency band can correspond to link 141 between computingdevice 150 and wireless network access node 110. The second frequencyband is configured to be a low-latency link and is therefore denoted LLin FIG. 4A. This second frequency band can correspond to link 142between computing device 150 and client device 130.

FIG. 4A illustrates a first FDM-TDM allocation 412 that is on the f1frequency band and a second FDM-TDM allocation 422 that is on the f2frequency band. Dashed line 432 illustrates the time a nominal FDM-TDMchannel switch would occur between allocation 412 and allocation 422.Transmission (BT) 451 is illustrated on the f1 frequency band.Transmission 451 begins before the nominal FDM-TDM channel switch wouldhave occurred (as shown by line 432), and ends after the nominal FDM-TDMchannel switch would have occurred. Accordingly, allocation 412 isillustrated in FIG. 4A as being extended by t₃ in order to entirelyencompass the time that transmission 451 is occurring. Thus, the totalduration of allocation 412 after being extended is t_(a3)=t_(a0)+t₃.Likewise, allocation 422 is illustrated in FIG. 4A as being shorted byt₃ to a duration of t_(b3)=t_(b0)−t₃. This helps maintain (at least anaverage) a FDM-TDM cycle time of t_(cyc)=t_(a3)+t_(b3)=t_(a0)+t_(b0). Inan example, transmission 451 can be a beacon or other type transmissionsent by wireless network access node 110 that computing device 150should not ignore.

FIG. 4B is a diagram illustrating an extended stay on a low-latencychannel. In FIG. 4B, the horizontal axis represents time, and thevertical axis represents frequency. A first frequency band, or channel,(f1) is shown above the horizontal axis. A second frequency band (f2) isshown below the horizontal axis. The first frequency band is configuredto be a high-throughput link and is therefore denoted HT in FIG. 4B.This first frequency band can correspond to link 141 between computingdevice 150 and wireless network access node 110. The second frequencyband is configured to be a low-latency link and is therefore denoted LLin FIG. 4B. This second frequency band can correspond to link 142between computing device 150 and client device 130. In an embodiment,link 141 can be configured to be a low-latency link and is thereforecorrespond to LL in FIG. 4B. Likewise, in an embodiment, link 142 can beconfigured to be a high-throughput link and therefore correspond to HTin FIGS. 4A-4C.

FIG. 4B illustrates a first FDM-TDM allocation 423 that is on the f2frequency band and a second FDM-TDM allocation 421 that is on the f1frequency band. Dashed line 433 illustrates the time a nominal FDM-TDMchannel switch would occur between allocation 423 and allocation 421.Transmission (CT) 452 is illustrated on the f2 frequency band.Transmission 452 begins before the nominal FDM-TDM channel switch wouldhave occurred (as shown by line 433), and ends after the nominal FDM-TDMchannel switch would have occurred. Accordingly, allocation 423 isillustrated in FIG. 4B as being extended by t₄ in order to entirelyencompass the time that transmission 452 is occurring. Thus, the totalduration of allocation 423 after being extended is t_(b4)=t_(b0)+t₄.Likewise, allocation 421 is illustrated in FIG. 4B as being shorted byt₄ to a duration of t_(a4)=t_(a0)−t₄. This helps maintain (at least anaverage) a FDM-TDM cycle time of t_(cyc)=t_(a4)+t_(b4)=t_(a0)+t_(b0). Inan example, transmission 452 can be a data transmission sent by clientdevice 130 that computing device 150 should not ignore.

FIG. 5 is a flowchart illustrating a method of scheduling a transmissionby a client device. The steps illustrated in FIG. 5 may be performed byone or more elements of communication system 100. A high-throughput linkthat uses a wireless interface radio to communicate with an access nodeusing a first frequency band and a first series of time allocations isconfigured (502). For example, computing device 150 may configure link141 as a high-throughput link that is periodically operates on a firstfrequency band during a first set of allocated time durations.

A low-latency link that uses the wireless interface radio to communicatewith at least one client device using a second frequency band and asecond series of time allocations is configured (504). For example,computing device 150 may configure link 142 as a low-latency link thatis periodically operates on a second frequency band during a second setof allocated time durations.

A first time indicator is sent to a first client device that iscommunicating via the second frequency band. In response to the firsttime indicator, the client device selects a first time to transmit thatis during a one of the second series of time allocations (506). Forexample, computing device 150 may send a message to client device 130instructing client device 130 to ‘wake up’ at a selected time (or,roughly equivalently, is to remain ‘asleep’ for a selected period). Inresponse to this message, client device 130 selects a time to ‘wake up’and send data or otherwise communicate with computing device 150 vialink 142.

The first time indicator may be specified as an absolute time orreferenced to, for example, a boundary (beginning or end) of one of thefirst or second series of time allocations, or a boundary between onesof the first and second series of time allocations. Depending on thetime selected by the client device, when the client ‘wakes up’ andtransmits, computing device 150 may need to extend or shorten one ormore of the first and second series of time allocations as describedherein.

It should also be understood that, in an embodiment, the configuredroles of links 141 and 142 may be swapped. In other words, link 141 maybe configured to be a low-latency link and link 142 may be configured tobe a high-throughput link.

FIG. 6 is a diagram illustrating a scheduled transmission. In FIG. 6,the horizontal axis represents time, and the vertical axis representsfrequency. A first frequency band, or channel, (f1) is shown above thehorizontal axis. A second frequency band (f2) is shown below thehorizontal axis. The first frequency band is configured to be ahigh-throughput link and is therefore denoted HT in FIG. 6. This firstfrequency band can correspond to link 141 between computing device 150and wireless network access node 110. The second frequency band isconfigured to be a low-latency link and is therefore denoted LL in FIG.6. This second frequency band can correspond to link 142 betweencomputing device 150 and client device 130. In an embodiment, link 141can be configured to be a low-latency link and is therefore correspondto LL in FIG. 6. Likewise, in an embodiment, link 142 can be configuredto be a high-throughput link and therefor correspond to HT in FIG. 6.

FIG. 6 illustrates a first FDM-TDM allocation 621 that is on the f2frequency band. Following allocation 621, a second FDM-TDM allocation611 that is on the f1 frequency band is illustrated. Followingallocation 611, a third FDM-TDM allocation 621 that is on the f2frequency band is illustrated. A transmission with a time indicator(t_(w)) 653 is illustrated as occurring during time allocation 621. Thetime indicator 653 determines when transmission 654 is to occur (e.g.,t_(w) may specify a ‘wake up’ time for client device 130). Timeindicator 653 is illustrated in FIG. 6 as being referenced to theboundary between allocation 621 and 611.

FIG. 7 is a block diagram illustrating a multi-channel single radioWi-Fi communication system. In FIG. 7, communication system 700comprises Wi-Fi access point 710, network 720, client device 730, clientdevice 731, and computing device 750. Computing device 750 includesWi-Fi radio 751. Wi-Fi access point 710 is operatively coupled tonetwork 720. Wi-Fi access point 710 is operatively coupled to computingdevice 750 by wireless link 741. Client device 730 is operativelycoupled to computing device 750 by wireless link 142. Client device 731is operatively coupled to computing device 750 by wireless link 143.

Wi-Fi access point 710 is a network element capable of providingwireless communication to wireless devices (e.g., computing device 150)according to one or more the Wi-Fi (802.11) standards and its variants.Wi-Fi access point 710 can be, for example, one or more of a Wi-Fiaccess point (node), a Wi-Fi hotspot, a Wi-Fi gateway, a basetransceiver station, a radio base station, an eNodeB device, or anenhanced eNodeB device. Wi-Fi access point 710 is connected to network720. Example devices that may be, comprise, and/or include Wi-Fi accesspoint 710 include, but are not limited to, example wireless capabledevice 2100 (described herein with reference to FIG. 21) and/or examplecomputer system 2200 (described herein with reference to FIG. 22).

Network 720 is a wide area communication network that can provide wiredand/or wireless communication to Wi-Fi access point 710. Network 720 andcan comprise wired and/or wireless communication networks that includeprocessing nodes, routers, gateways, physical and/or wireless data linksfor carrying data among various network elements, including combinationsthereof, and can include a local area network, a wide area network, andan internetwork (including the Internet). Network 720 can also comprisewireless networks, including base station, wireless communication nodes,telephony switches, internet routers, network gateways, computersystems, communication links, or some other type of communicationequipment, and combinations thereof. Wired network protocols that may beutilized by network 720 comprise Ethernet, Fast Ethernet, GigabitEthernet, Local Talk (such as Carrier Sense Multiple Access withCollision Avoidance), Token Ring, Fiber Distributed Data Interface(FDDI), and Asynchronous Transfer Mode (ATM). Links between elements ofnetwork 720, can be, for example, twisted pair cable, coaxial cable orfiber optic cable, or combinations thereof. Wireless network protocolsthat may be utilized by communication system 700 may comprise one ormore IEEE 802 specified protocols,

Other network elements may be present in network 720 to facilitatecommunication with Wi-Fi access point 710 but are omitted for clarity,such as base stations, base station controllers, gateways, mobileswitching centers, dispatch application processors, and locationregisters such as a home location register or visitor location register.Furthermore, other network elements may be present to facilitatecommunication between among elements of communication system 700 whichare omitted for clarity, including additional computing devices, clientdevices, access nodes, routers, gateways, and physical and/or wirelessdata links for carrying data among the various network elements.

In an embodiment, computing device 750 may be any device, system,combination of devices, or other such communication platform capable ofwirelessly communicating, using a single radio 751, with Wi-Fi accesspoint 710 using a Wi-Fi specified protocol, and wirelessly communicatingwith client devices 730 and 731 using a latency optimized protocolspecified for low latency. In another embodiment, computing device 750may be any device, system, combination of devices, or other suchcommunication platform capable of wirelessly communicating, using asingle radio 751, with Wi-Fi access point 710 using a Wi-Fi specifiedprotocol, and wirelessly communicating with client devices 730 and 731using a Wi-Fi Direct specified protocol. Computing device 750 canoperate using a single wireless interface radio 751 to establishwireless links 741, 742, and 743 and communicate concurrently with Wi-Fiaccess point 710 and client devices 730 and 731, respectively. Computingdevice 750 may connect to Wi-Fi access point 710 as a client of a Wi-Finetwork (e.g., a wireless network associated with a single BSSID)provided by Wi-Fi access point 710 that also connects to network 720.Client devices 730 and 731 may connect to a wireless network provided bycomputing device 750. The wireless network provided by computing device750 may be a peer-to-peer type wireless network (e.g. a latencyoptimized client network or a Wi-Fi Direct network.) Computing device750 may include hardware and/or software that allows computing device750 to function as what is known as a ‘soft access point’ or ‘soft-AP’for a latency optimized or a WFD network provided by computing device750 to client device 730 and client device 731.

Computing device 750 may include hardware and/or software to establishand maintain multiple client connections 755 and 756 to Wi-Fi accesspoint 710 as clients of a Wi-Fi network provided by Wi-Fi access point710. Likewise, computing device 750 may include hardware and/or softwareto establish and maintain a connection or apparent connection to a Wi-Fiaccess point that is not Wi-Fi access point 710. Client connection 755is typically used as the client to carry traffic between Wi-Fi accesspoint 710 and computing device 750. Client connections 756 and 757 arenot typically used to carry traffic, and may thus be referred to as‘virtual’ clients. Example devices that may be, comprise, and/or includecomputing device 750 include, but are not limited to, example wirelesscapable device 2100 (described herein with reference to FIG. 21) and/orexample computer system 2200 (described herein with reference to FIG.22).

Client devices 730 and 731 may be, for example, one or more of a videogame controller, computer peripheral (e.g., mouse, keyboard, printer,speakers), a mobile phone, a wireless phone, a wireless modem, apersonal digital assistant (PDA), a voice over internet protocol (VoIP)phone, a voice over packet (VOP) phone, or a soft phone, as well asother types of devices or systems that can exchange data with computingdevice 750 via client links 742 and 743. Other types of communicationplatforms are possible. Example devices that may be, comprise, and/orinclude client device 730 and/or client device 731 include, but are notlimited to, example wireless capable device 2100 (described herein withreference to FIG. 21) and/or example computer system 2200 (describedherein with reference to FIG. 22).

In an embodiment, computing device 750 controls and/or configures Wi-Firadio 751 to implement a combination of frequency division multiplexing(FDM) and time division multiplexing (TDM) that alternates betweencommunication via wireless link 741 and wireless links 742 and 743. Inother words, Wi-Fi radio 751 both switches between at least two Wi-Fichannels to implement frequency division multiplexing, and alsocommunicates on a respective Wi-Fi channel during a respective series ofnon-overlapping time allocations to implement time divisionmultiplexing. Thus, Wi-Fi radio 751 may periodically communicate withWi-Fi access point 710 during selected time periods using a first Wi-Fichannel (a.k.a., ‘access point channel’ or ‘AP channel’), andcommunicate with one or more of client device 730 and client device 731using a second Wi-Fi channel (a.k.a., ‘client channel’) during the restof the time. In an embodiment, the time periods are selected such thatwireless link 741 is configured as a high-throughput link and wirelesslinks 742 and 743 are configured as a low-latency links. In anotherembodiment, the time periods are selected such that wireless link 741 isconfigured as a low-latency link and wireless links 742 and 743 areconfigured as a high-throughput links.

Virtual clients 756 and 757 can be used to manipulate the timing oftransmissions between computing device 750 and Wi-Fi access point 710 onthe AP channel. In order to manipulate the timing of communication onthe AP channel, one or more of virtual client 756 and virtual client 757can be used by computing device 750 to set busy indicators, and/ordevice sleep/wake indicators used by Wi-Fi access point 710. The busyindicators, and/or device sleep/wake indicators set by one or more ofclients 755-757 can alter the timing of transmissions of the AP channel(e.g., by setting the network access vector—NAV.) These busy indicators,and/or device sleep/wake indicators set by one or more of clients755-757 can alter the timing of certain types of transmissions (e.g.,broadcast or multicast transmissions) on the AP channel.

Wi-Fi access point 710 may be unaware that computing device 750 is usingFDM-TDM channel switching to communicate via wireless links 741 and 742using a single radio 751. Accordingly, Wi-Fi access point 710 mayfunction under an assumption that wireless link 741 is always on thesame channel and is conforming to the Wi-Fi protocol associated withWi-Fi access point 710.

In an embodiment, computing device 750 may control radio 751 to deviatefrom a strict fixed time channel switching scheme in order to maintainreliable communication with both client devices 730 and 731, and Wi-Fiaccess point 710. In typical operation, computing device 750communicates alternately with Wi-Fi access point 710 via the AP channeland with client devices 730 and 731 via the client channel. Whencommunicating with Wi-Fi access point 710, radio 751 is configured touse the AP channel. When communicating with client devices 730 and 731,radio 751 is configured to use the client channel. At nominally fixedintervals (i.e., TDM), radio 751 is switched between the AP channel andthe client channel (i.e., FDM)

Wi-Fi access point 710 may be sending (or will be unable to complete) abeacon frame when the time for an FDM-TDM channel switch between the APchannel and the client channel occurs. If the switchover of radio 751between the AP channel and the client channel were to occur at thatpredetermined time, at least part of the information in the beacon framewould be missed by computing device 750. In an embodiment, computingdevice 750 does not switch between channels at the predetermined timeand instead delays the switch in order to complete the reception of thebeacon frame from Wi-Fi access point 710. Computing device 750 may delaythe FDM-TDM channel switch by a predetermined amount of time (e.g.,several milliseconds) that allows for the complete reception of anybeacon frame which would not complete before the time nominallyscheduled for the FDM-TDM channel switch.

After a FDM-TDM channel switch between the AP channel and the clientchannel is delayed, computing device 750 may then shorten the next (orany subsequent) time spent on the client channel. This adjustment can beused to maintain an average (or nominal) period for cycling between theAP channel and the client channel. This adjustment can also be used tohelp maintain a sleep/wake schedule synchronization with client devices730 and 731.

Client device 730 may be sending (or will be unable to complete) a datatransmission at the time scheduled for a FDM-TDM channel switch betweenthe client channel and the AP channel. If the switchover of radio 751were to occur at that predetermined time, at least part of theinformation transmitted by client device 730 could be missed bycomputing device 750. In an embodiment, computing device 750 does notswitch between Wi-Fi channels at the predetermined time and insteaddelays the channel switch in order to complete the reception of thetransmission from client device 730. Computing device 750 may delay theFDM-TDM channel switch by a predetermined amount of time (e.g., severalof milliseconds) that allows for the complete reception of any clientdevice 730 or 731 transmission which would not complete before the timenominally scheduled for the FDM-TDM channel switch.

After a FDM-TDM channel switch is delayed to allow reception of thebeacon frame to complete, computing device 750 may then shorten the next(or any subsequent) time allocation spent on the AP channel. Thisadjustment can be used to maintain an average (or nominal) period forcycling between Wi-Fi channels. This adjustment can also be used to helpmaintain a sleep/wake schedule synchronization with client devices 730and 731.

In an embodiment, the relative time spent communicating via the APchannel versus the client channel can be varied by computing device 750according to the traffic on one or both of the Wi-Fi channels. Inanother embodiment, the relative time spent communicating via the APchannel versus the client channel can be varied by computing device 750based on one or more of: an application being run on computing device750, a device classification of a client device 730 or 731 (e.g., mousevs. keyboard vs. game controller, etc.) In this manner, throughput onthe AP channel and latency the client channel can be optimized accordingto the activity on the channels and/or expected needs of an applicationand/or a client device 730 or 731.

In an embodiment, computing device 750 sends scheduling and/or controlinformation to client device 730 and client device 731 using the clientchannel. This information can be used to prevent, or help prevent,attempts by client device 730 and/or client device 731 to use the clientchannel to transmit while radio 751 is configured to listen to only theAP channel. For example, computing device 750 may send a recommendedsleep duration to client device 730. This sleep duration can be selectedby computing device 750 such that client device 730 will (or is likelyto) remain asleep during period(s) of time when radio 751 is configuredto listen on the AP channel.

As described herein, computing device 750 regularly spends at least sometime with radio 751 configured to communicate via the client channel.When radio 751 is configured to communicate client channel, it cannotcommunicate via the AP channel. In an embodiment, before performing aFDM-TDM channel switch from the AP channel to the client channel,computing device 750 sends an indicator to Wi-Fi access point 710 (e.g.,using a NULL frame to specify a ‘sleep’ or ‘power save’ duration.) Thisindicator informs Wi-Fi access point 710 that, as far as Wi-Fi accesspoint 710 is concerned, computing device 750 is going to sleep and willnot be receiving communication via the AP channel. Wi-Fi access point710 confirms receipt of this indicator by sending computing device 750an acknowledgement message (e.g., ACK frame) via the AP channel. Whencomputing device 750 receives the acknowledgement message via the APchannel, computing device 750 may perform an FDM-TDM channel switch tothe client channel (or go to sleep.)

Wi-Fi access point 710 may not respond with the acknowledgement to thepower save indicator before the predetermined time for the FDM-TDMchannel switch from the AP channel to the client channel. This lack ofan acknowledgement may occur because Wi-Fi access point 710 is busy withother traffic (e.g., sending a beacon frame) or interference (e.g.,traffic on another wireless network operating on the same or nearbychannels.) Computing device 750 may then monitor the AP channel and theclient channel simultaneously. Computing device 750 may monitor the APchannel in order to receive the acknowledgement frame. Computing device750 may monitor the client channel in order to receive transmissionsfrom a client device 730 and respond to these transmissions within aselected maximum latency time period. Computing device 750 may monitorboth the AP channel and the client channel simultaneously by receivingand demodulating communication on both the AP channel and the clientchannel. For example, since the AP channel and the client channel bothuse orthogonal frequency division multiplexing (OFDM), Computing device750 may monitor both the AP channel and the client channel by receivingat least the OFDM carriers associated with the AP channel and the clientchannel, discarding data corresponding to OFDM carriers not used by theAP channel and the client channel (e.g., intervening channels when theAP channel and the client channel are on non-contiguous Wi-Fi channels),and then separately (i.e., by channel) processing the data associatedwith the respective OFDM carriers for the AP channel and the clientchannel. In an embodiment, appropriate filters and/or filter banks maybe used for performing the desired separation.

Computing device 750 may have data to transmit to client device 730 whenWi-Fi access point 710 has not responded to the power save indicatorbefore the predetermined time for the FDM-TDM channel switch from the APchannel to the client channel. To prevent Wi-Fi access point 710 fromtransmitting on the AP channel while computing device 750 istransmitting data to a client device 730 or 731 after the switch to theclient channel, computing device 750 can send a transmission on the APchannel. This transmission is sent associated with an identifier (e.g.,MAC address) such that the transmission appears to be from a device thatis not connected to Wi-Fi access point 710. This transmission canindicate a transmission duration that corresponds to the time thecomputing device 750 needs to transmit on the client channel. In thismanner, the Wi-Fi collision avoidance algorithm used by Wi-Fi accesspoint 710 will prevent the Wi-Fi access point 710 from transmitting onthe client channel for the specified transmission duration. Aftercomputing device 750 has completed its transmission on the clientchannel, computing device 750 can switch into the aforementioned modewhereby computing device 750 simultaneously monitors the AP channel andthe client channel.

To prevent (or help prevent) cases where Wi-Fi access node 710 isdelayed from sending an acknowledgment due to a beacon frametransmission (or impending beacon frame transmission), computing device750 can adjust the time allocations (and/or timing of the FDM-TDMchannel switches) spent the AP channel and the client channel such thatthe beacon frame transmissions occur while radio 751 is known to be (orvery likely to be) configured to be on the AP channel.

Broadcast or multicast frames being sent by Wi-Fi access point 710 mayalso cause computing device 750 and/or Wi-Fi access point 710 fromcommunicating or responding to a power save message. Computing device750 can send a transmission on the AP channel that appears to be from adevice that is connected to Wi-Fi access point 710, but where thatdevice is not identified (e.g., by MAC address) as being computingdevice 750 (i.e., a ‘virtual’ client of Wi-Fi access point 710 createdby computing device 750 for this purpose.) This transmission canindicate to Wi-Fi access point 710 that the virtual client device willbe sleeping at all times except those close to the beacon time. Sincebroadcast/multicast frames are sent at times when all of the clients ofWi-Fi access point 710 are awake, Wi-Fi access point 710 will beconstrained to scheduling broadcast/multicast frames close to the beacontime. This at least limits the effect of broadcast/multicast frames toswitchover times that are close to the beacon time.

Aggregated frames being sent by Wi-Fi access point 710 may also causecomputing device 750 and/or Wi-Fi access node 710 from communicating orresponding to a power save message. Since Wi-Fi access point 710 is busysending these aggregated frames, computing device 750 may not be able tosend the power save indicator to Wi-Fi access point 710 and/or receivean acknowledgement. When this occurs, computing device 750 may elect tocontinue to switch between the AP channel and the client channelaccording to the FDM-TDM time allocations without informing Wi-Fi accesspoint 710 that computing device 750 is going to sleep. By continuing toswitch channels without informing Wi-Fi access point 710, computingdevice 750 may switch away from the AP channel and the client channeland then back to the AP channel before the aggregated frame transmissioncompletes. By returning to the AP channel before the frame transmissioncompletes, computing device 750 may not miss a transmission from Wi-Fiaccess point 710, or need to re-establish link 741.

FIG. 8 is a flowchart illustrating a method for setting a transmissiontime by a client device. The steps illustrated in FIG. 8 may beperformed by one or more elements of communication system 100 and/orcommunication system 700. A low-latency link that uses a first frequencyband and a first series of time allocations is configured (802). Forexample, client device 730 and computing device 750 and Wi-Fi accesspoint 710 may establish and provision link 742 on the client channel.Computing device 750 may set parameters (such as timeintervals/allocations for FDM-TDM channel switching) that allow clientdevice 730 to communicate with computing device 730 via the clientchannel.

A time indicator from the access point is received via the low-latencylink (804). For example, client device 730 may receive a time indicator653 from computing device 750 instructing client device 730 to ‘wake up’at a selected time (or, equivalently, is to remain ‘asleep’ for aselected period). In response to the time indicator, the client deviceis configured to select a transmit/wake-up time that is during a firstone of the first series of time allocations (804). For example, inresponse to time indicator 653, client device 730 can configure itselfto wake up at a time corresponding the time indicator 653 received fromcomputing device 750. Computing device 750 can select this wake up timecan fall within a time allocation for the client channel (e.g.,transmission 654.)

Optionally, if there is a collision at the selected transmit/wake-uptime, a new transmit/wake-up time is selected (808). For example, if, atthe transmit/wake-up time, client device 730 detects that another deviceis transmitting at that time, client device 730 can select a new time towake-up/transmit according a Wi-Fi collision avoidance procedure.

FIG. 9 is a diagram illustrating multi-channel reception by a singleradio. As discussed herein, computing device 750 can monitor both the APchannel and the client channel. In FIG. 9, an example channel spectrumof Wi-Fi channel 1 (e.g., the AP channel) and Wi-Fi channel 6 (e.g., theclient channel) are illustrated. Both channels are demodulated into OFDMcarriers. Both channels may be demodulated into OFDM carriers byconfiguring radio 751 as if radio 751 were receiving a 40 MHz wide Wi-Fichannel that encompasses the two 20 MHz Wi-Fi channels 1 and 6.Alternatively, configuring radio 751 as if radio 751 were receiving an80 MHz Wi-Fi channel can be used to receive contiguous or non-contiguous20 MHz Wi-Fi channels, or contiguous 40 MHz wide channels. Likewise,configuring radio 751 as if radio 751 were receiving a 160 MHz Wi-Fichannel can be used to receive contiguous or non-contiguous 20 or 40 MHzWi-Fi channels, or contiguous 80 MHz wide channels.

FIG. 10 is a diagram illustrating multi-channel reception to preventholdover. In FIG. 10, the horizontal axis represents time, and thevertical axis represents frequency. A first Wi-Fi channel is shown abovethe horizontal axis. A second Wi-Fi channel is shown below thehorizontal axis. The first Wi-Fi channel is operated to be ahigh-throughput link and is therefore denoted the AP channel in FIG. 10.This first frequency band can correspond to the channel used by link 741between computing device 750 and Wi-Fi access point 710. The secondfrequency band is operated to be a low-latency link and is thereforedenoted the client channel in FIG. 10. This second frequency band cancorrespond to the channel used by links 142 and 143 between computingdevice 750 and client devices 730 and 731, respectively.

FIG. 10 illustrates successive time allocations 1010, 1011, 1012, and1013 on the AP channel. Also illustrated are time allocations 1021 and1022 on the client channel. Allocation 1021 corresponds in time toallocation 1010. Allocation 1022 corresponds in time to allocation 1012.Allocations 1011, 1013, 1021 and 1022 are labeled to indicate bothreceiving and transmitting activities. Allocations 1010 and 1012 arelabeled to indicate just receiving. It should be understood that radio751 may not be able to simultaneously transmit and receive on a channel.Thus, in this case, it should be understood that the transmit andreceive activities of radio 751 are time-division multiplexed accordingto the specified protocol on the respective channel. For example, radio751 may spend part of the time in allocation 1011 receiving and part ofthe time transmitting. The switching between receiving and transmittingmay be governed by the Wi-Fi protocol. In another example, radio 751 mayspend part of the time in allocation 1022 receiving and part of the timetransmitting. The switching between receiving and transmitting may begoverned by the latency optimized client network protocol being used onthe client channel.

In allocation 1011, a power save (i.e., ‘going to sleep’) indicator 1051is transmitted. Indicator 1051 is transmitted by computing device 750.In allocation 1012, an acknowledgement 1052 to indicator 1051 istransmitted. Acknowledgement 1052 is transmitted by Wi-Fi access point710 in response to receiving indicator 1051. It should be noted,however, that since allocation 1012 and allocation 1022 correspond intime, and allocation 1022 is nominally for client channel 1022,computing device 750 configures radio 751 in the multi-channel receptionmode described herein (as further detailed herein with reference to atleast FIG. 9 as an example). With radio 751 operating such that it canreceive on the AP channel while both receiving and transmitting on theclient channel, computing device 750 is able to receive acknowledgment1052 in allocation 1012.

FIG. 11 is a diagram illustrating multi-channel transmission. In FIG.11, the horizontal axis represents time, and the vertical axisrepresents frequency. A first Wi-Fi channel is shown above thehorizontal axis. A second Wi-Fi channel is shown below the horizontalaxis. The first Wi-Fi channel is operated to be a high-throughput linkand is therefore denoted AP channel in FIG. 11. This first frequencyband can correspond to the channel used by link 741 between computingdevice 750 and Wi-Fi access point 710. The second frequency band isoperated to be a low-latency link and is therefore denoted clientchannel in FIG. 11. This second frequency band can correspond to thechannel used by link 142 and 143 between computing device 750 and clientdevices 730 and 731, respectively.

FIG. 11 illustrates successive time allocations 1110, 1111, 1112, and1113 on the AP channel. Also illustrated are successive allocations1120, 1121, and 1122 on the client channel. Allocation 1120 correspondsin time to allocation 1110. Allocation 1121 corresponds in time toallocation 1111. Allocation 1122 corresponds in time to allocation 1112.In allocation 1110 a busy indicator (NAV) 1153 is transmitted bycomputing device 750 on the AP channel. In allocation 1120 (possiblysimultaneous with busy indicator 1153) a busy indicator (NAV) 1153 istransmitted by computing device 750 on the client channel. In anembodiment, busy indicators 1153 and 1154 correspond to the Wi-Finetwork access vector (NAV) in a Wi-Fi frame. It should be noted, thatsince busy indicator 1153 and busy indicator 1154 correspond in time,and busy indicator 1153 is not associated with a device that isconnected on the AP channel, Wi-Fi access point 710 will respond to busyindicator 1153 by treating the AP channel as busy for all (or part—asspecified by indicator 1153) of allocation 1111. Thus, Wi-Fi accesspoint 710 will not transmit during allocation 1111 on the AP channelthereby allowing computing device 750 to transmit and receive on (atleast) the client channel during allocation 1121.

FIG. 12 is a diagram illustrating client device following. Whencomputing device 750 is operating on the client channel, client device730 sends communication #1 to computing device 750 via the clientchannel. In response, computing device 750 sends a response back toclient device 730 via the client channel. This is normal operationduring FDM-TDM allocations on the client channel.

After a FDM-TDM channel switch has occurred and computing device 750 isoperating on the AP channel, client device 730 sends communication #2 tocomputing device 750 via the client channel. However, since computingdevice 750 is operating on the AP channel, computing device 750 does notreceive communication #2 and therefore does not send a response toclient device 730 via the client channel.

Responsive to not receiving a response via the client channel, clientdevice 730 resends communication #2 via the AP channel. This time, sincecomputing device 750 is operating on the AP channel, computing device750 receives the retried communication #2 via the AP channel andtherefore sends a response to client device 730 via the AP channel. Inresponse to receiving the response via the AP channel, client device 730send communication #3 via the AP channel. Thus, it should be understoodthat in an embodiment, client device 730 can ‘follow’ computing device750 from the client channel to the AP channel (and back).

FIG. 13 is a diagram that illustrates setting an access nodetransmission time. The processes illustrated in FIG. 13 may be performedby one or more elements of communication system 100 and/or communicationsystem 700. At the start of the diagram, ‘real’ client 755 of computingdevice 750 and ‘virtual’ client 756 are connected to Wi-Fi access point710. Virtual client 757, however, is not (and normally will never be)connected to Wi-Fi access point 710. Client 755 of computing device 750sends a power save (or ‘sleep’) indicator message to Wi-Fi access point710 via the AP channel. Computing device 750 may have client 755 sendthe indicator message to Wi-Fi access point 710 so that computing device750 will appear ‘asleep’ to Wi-Fi access point 710. This allowscomputing device 750 to configure radio 751 to operate on the clientchannel during a client channel time allocation. However, for at leastone of the reasons described herein (e.g., Wi-Fi access point 710 isbusy with other traffic, beacon frame, etc.) Wi-Fi access point 710 doesnot send a response to computing device 750.

In response to not receiving a response from Wi-Fi access point 710 viathe AP channel, computing device 750 has virtual client 757 send atransmission on the AP channel. This transmission includes a networkaccess vector (NAV) selected to give computing device 750 (and client755 of computing device 750, in particular) time to operate on theclient channel by making the AP channel appear to be busy to Wi-Fiaccess point 710. When the time set by virtual client 757 expires, Wi-Fiaccess point 710 can send a transmission to computing device 750 (andclient 755 of computing device 750, in particular) via the AP channel.

FIG. 14 is a diagram that illustrates setting a broadcast/multicasttransmission time. The processes illustrated in FIG. 13 may be performedby one or more elements of communication system 100 and/or communicationsystem 700. At the start of the diagram, ‘real’ client 755 of computingdevice 750 and ‘virtual’ client 756 are connected to Wi-Fi access point710. Virtual client 757, however, is not (and normally will never be)connected to Wi-Fi access point 710. Virtual client 756 of computingdevice 750 sends a power save (or ‘sleep’) indicator message to Wi-Fiaccess point 710 via the AP channel. Computing device 750 has client 756send this indicator message to Wi-Fi access point 710 so that virtualclient 756 will appear ‘asleep’ to Wi-Fi access point 710. Computingdevice 750 times the sending of this indicator message to Wi-Fi accesspoint 710 so that virtual client 756 will only appear ‘awake to Wi-Fiaccess point 710 around time that Wi-Fi access point 710 will be sendinga beacon frame. Since broadcast/multicast frames are only sent when allthe clients connected to Wi-Fi access point 710 (i.e., client 755 andvirtual client 756) are awake, broadcast/multicast frames are confinedto being sent during the ‘awake’ times of virtual client 756. Thus, thesleep/wake times of virtual client 756 can be used to control whenbroadcast/multicast frames are sent by Wi-Fi access point 710.

After receiving the power save message from virtual client 756, Wi-Fiaccess point 710 waits for the ‘media busy’ time set by virtual client756 to expire. When the time set by virtual client 756 expires, Wi-Fiaccess point 710 can send broadcast/multicast frames to computing device750 (and client 755 of computing device 750, in particular) via the APchannel.

FIG. 15 is a diagram illustrating time allocations to receive beacontransmissions. In FIG. 15, beacon transmissions 1561, 1562, and 1563 byWi-Fi access point 710 are illustrated. In addition, AP channelallocations 1511, 1512, 1513, 1514, and 1515, and client channelallocations 1521, 1522, 1523, and 1524 are illustrated. In FIG. 15, APallocations AP channel allocations 1511, 1512, 1513, 1514, and 1515,alternate with, but do not overlap in time, client channel allocations1521, 1522, 1523, and 1524. AP allocations 1511, 1513, and 1515,however, are timed so that computing device 750 can receive beacontransmissions 1561, 1562, and 1563. This is illustrated in FIG. 15,respectively, by arrow 1571 between beacon 1561 and allocation 1511,arrow 1572 between beacon 1562 and allocation 1513, and arrow 1573between beacon 1563 and allocation 1515.

FIG. 16 is a diagram illustrating an aggregated frame transmission. InFIG. 1165, aggregated frame transmission 1661 by Wi-Fi access point 710is illustrated. In addition, AP channel allocations 1611, 1612, 1613,1614, and 1615, and client channel allocations 1621, 1622, 1623, and1624 are illustrated. In FIG. 16, AP allocations AP channel allocations1611, 1612, 1613, 1614, and 1615, alternate with, but do not overlap intime, client channel allocations 1621, 1622, 1623, and 1624. Aggregatedframe transmission 1661, however, begins during AP channel allocation1611, continues through client allocation 1621, and ends during APchannel allocation 1612. Thus, since access point was transmittingduring the entire time computing device 750 was operating on the clientchannel, computing device 750 does not miss any data from Wi-Fi accesspoint 710.

FIG. 17 is a flowchart illustrating a method of operating acommunication system. The steps illustrated in FIG. 17 may be performedby one or more elements of communication system 100 and/or communicationsystem 700. A first wireless interface link is established tocommunicate with an access node using a first channel of a frequencyband (1702). For example, computing device 750 may establish link 741with Wi-Fi access point 710 using a channel designated as the APchannel. The AP channel is specified as one of a plurality of channelsof a country dependent Wi-Fi frequency band. A second wireless interfacelink is established to communicate with a client device using a secondchannel of the frequency band (1702). For example, computing device 750may establish link 742 with client device 730 using a channeldesignated, by computing device 750, as the client channel. Like the APchannel, the client channel is specified as one of a plurality ofchannels of a country dependent Wi-Fi frequency band.

Via the first wireless interface link, a first message to the accessnode indicating the first wireless interface link is to enter a dormantstate is sent (1706). For example, computing device 750 may send, toWi-Fi access point 710, a power save indicator informing Wi-Fi accesspoint 710 that computing device 750 will not be in communication for aperiod of time.

Data from the access node via the first channel and data from the clientdevice via the second channel is concurrently received by demodulating awide channel comprising the first channel and the second channel. Theconcurrently received data including an indicator that the access nodehas received the first message (1708). For example, radio 751 may beconfigured to receive, demodulate, separate, and decode the OFDMcarriers of the AP channel and the client channel as described herein(e.g., by demodulating a 40 MHz channel comprising two 20 MHz channels.)This allows computing device 750 to monitor the AP channel for anacknowledgement from Wi-Fi access point 710, and to monitor the clientchannel for a communication from a client device 730.

FIG. 18 is a flowchart illustrating a method of operating a clientdevice. The steps illustrated in FIG. 18 may be performed by one or moreelements of communication system 100 and/or communication system 700. Alow-latency link between a client device and a soft access point isconfigured (1802). In an embodiment, the low-latency link uses a firstfrequency band and a first series of time allocations while a second(e.g., high-throughput) link uses a second frequency band and a secondseries of time allocations. For example, client device 730 and computingdevice 750 may be configured to communicate via link 742 while computingdevice 750 and Wi-Fi access point 710 are configured to communicate vialink 741.

Via the low-latency link, a first message to the soft access point usingthe first frequency band and a one of a series of time allocations issent (1804). For example, client device 730 may send a Wi-Fi frame tocomputing device 750 using the client channel during a time allocationdesignated for operating on the client channel.

In response to not receiving, via the first frequency band, anacknowledgement associated with the first message, a retry of the firstmessage using a second frequency band and during the one of the seriesof time allocations is sent (1806). For example, in response to notreceiving an acknowledgement of the client channel, client device 730may send a retry of the Wi-Fi frame, during the time allocationdesignated for operating on the client channel, to computing device 750,using the AP channel.

In response to receiving, via the second frequency band, anacknowledgement associated with the retry of the first message, a secondmessage to the soft access point is sent using the second frequency bandand is sent during the one of the series of time allocations (1808). Forexample, client device 730 may send, in response to receiving anacknowledgement of the retry frame, additional messages/data during thetime allocation designated for operating on the client channel, tocomputing device 750, using the AP channel.

FIG. 19 is a flowchart illustrating a method of using a connectedvirtual client to constrain access point transmission timing. The stepsillustrated in FIG. 19 may be performed by one or more elements ofcommunication system 100 and/or communication system 700. A wirelessinterface radio is configured to communicate with a first access nodeusing a first frequency band and a first series of time allocations(1902). For example, radio 751 of computing device 750 may be configureby computing device 750 to communicate with Wi-Fi access point 710 usingthe AP channel during time allocations designated for operating usingthe AP channel.

The wireless interface radio is configured to communicate with a clientdevice using a second frequency band and a second series of timeallocations (1904). For example, radio 751 of computing device 750 maybe configured by computing device 750 to communicate with Wi-Fi device730 using the client channel during time allocations designated foroperating using the client channel.

With the access node, a first wireless communication link associatedwith a first MAC identifier is established (1906). For example,computing device 750 may establish a connection for client 755 withWi-Fi access point 710. With the access node, a second wirelesscommunication link associated with a second MAC identifier isestablished (1908). For example, computing device 750 may establish aconnection for virtual client 756 with Wi-Fi access point 710.

Information to constrain a timing that the access node will schedule atleast one transmission is transmitted associated to the second MACidentifier (1910). For example, computing device 750 may have radio 751make a transmission that is identified as coming from virtual client756. This transmission can set sleep/wake parameters used by Wi-Fiaccess point 710 to determine when to send certain transmissions (e.g.,broadcast/multicast transmissions). By setting these parameters with thetransmission that was identified as coming from virtual client 756,computing device 750 can constrain the timing of future transmissions byWi-Fi access point 710.

FIG. 20 is a flowchart illustrating a method of using a connectedvirtual client to constrain access point transmission timing. The stepsillustrated in FIG. 20 may be performed by one or more elements ofcommunication system 100 and/or communication system 700. A wirelessinterface radio is configured to communicate with a first access nodeusing a first frequency band and a first series of time allocations(2002). For example, radio 751 of computing device 750 may be configuredby computing device 750 to communicate with Wi-Fi access point 710 usingthe AP channel during time allocations designated for operating usingthe AP channel.

The wireless interface radio is configured to communicate with a clientdevice using a second frequency band and a second series of timeallocations (2004). For example, radio 751 of computing device 750 maybe configure by computing device 750 to communicate with Wi-Fi device730 using the client channel during time allocations designated foroperating using the client channel.

With the access node, a first wireless communication link associatedwith a first MAC identifier is established (2006). For example,computing device 750 may establish a connection for client 755 withWi-Fi access point 710.

Information to constrain a timing that the access node will schedule atleast one transmission is transmitted associated to a second MACidentifier that is not associated with a wireless communication linkwith the access node (2008). For example, computing device 750 may haveradio 751 make a transmission that is identified as coming from virtualclient 757. This transmission can set busy/free parameters used by Wi-Fiaccess point 710 that determine when to send certain transmissions(e.g., broadcast/multicast transmissions). By setting these parameterswith the transmission that was identified as coming from virtual client757, computing device 750 can constrain the timing of futuretransmissions by Wi-Fi access point 710.

Many of the functions, protocols, etc. described above may beimplemented with, contain, or be executed by one or more computersystems, processing circuits, hardware state machines, or other circuitblocks and/or circuit partitions. The methods described above may alsobe stored on a non-transitory computer readable medium and/orimplemented by state machines. Many of the elements of communicationsystem 100, and/or communication system 700 may be, comprise, or includewireless capable devices and/or nodes. This includes, but is not limitedto: wireless network access node 110, client device 130, computingdevice 150, Wi-Fi access node 710, client device 730, client device 731,and/or computing device 750.

FIG. 21 is a block diagram illustrating portions of an example wirelesscapable device. Wireless capable device 2100 comprises antenna 2106,transceiver circuit 2104, collision avoidance circuit 2110, tunercircuit 2108, timer circuit 2112, wireless interface layer controlcircuit 2114, higher level network protocol circuit 2116, and processor2118. antenna 2106, transceiver circuit 2104, collision avoidancecircuit 2110, tuner circuit 2108, timer circuit 2112, wireless interfacelayer control circuit 2114 may cooperate to implement one or more of thelower layers (e.g., physical layer 1) of the Open Systems Interconnect(OSI) model and the additional or modified functions associated withthat layer described herein. Processor 2118 and higher level networkprotocol circuit 2116 may cooperate to implement one or more of thehigher layers (e.g., MAC or IP layer) of the Open Systems Interconnectand the additional or modified functions of those layers describedherein.

The methods, systems and devices described above may be implemented incomputer systems, or stored by computer systems. The methods describedabove may also be stored on a non-transitory computer readable medium.Devices, circuits, and systems described herein may be implemented usingcomputer-aided design tools available in the art, and embodied bycomputer-readable files containing software descriptions of suchcircuits. This includes, but is not limited to one or more elements ofwireless network access node 110, client device 130, computing device150, Wi-Fi access node 710, client device 730, client device 731, and/orcomputing device 750, communication system 100, and/or communicationsystem 700, and their components. These software descriptions may be:behavioral, register transfer, logic component, transistor, and layoutgeometry-level descriptions.

Data formats in which such descriptions may be implemented are stored ona non-transitory computer readable medium include, but are not limitedto: formats supporting behavioral languages like C, formats supportingregister transfer level (RTL) languages like Verilog and VHDL, formatssupporting geometry description languages (such as GDSII, GDSIII, GDSIV,CIF, and MEBES), and other suitable formats and languages. Physicalfiles may be implemented on non-transitory machine-readable media suchas: 4 mm magnetic tape, 8 mm magnetic tape, 3½-inch floppy media, CDs,DVDs, hard disk drives, solid-state disk drives, solid-state memory,flash drives, and so on.

Alternatively, or in addition, the functionally described herein can beperformed, at least in part, by one or more hardware logic components.For example, and without limitation, illustrative types of hardwarelogic components that can be used include Field-programmable Gate Arrays(FPGAs), Application-specific Integrated Circuits (ASICs),Application-specific Standard Products (ASSPs), System-on-a-chip systems(SOCs), Complex Programmable Logic Devices (CPLDs), etc.

FIG. 22 illustrates a block diagram of an example computer system.Computer system 2200 includes communication interface 2220, processingsystem 2230, storage system 2240, and user interface 2260. Processingsystem 2230 is operatively coupled to storage system 2240. Storagesystem 2240 stores software 2250 and data 2270. Processing system 2230is operatively coupled to communication interface 2220 and userinterface 2260. Computer system 2200 may comprise a programmedgeneral-purpose computer. Computer system 2200 may include amicroprocessor. Computer system 2200 may comprise programmable orspecial purpose circuitry. Computer system 2200 may be distributed amongmultiple devices, processors, storage, and/or interfaces that togethercomprise elements 2220-2270.

Communication interface 2220 may comprise a network interface, modem,port, bus, link, transceiver, or other communication device.Communication interface 2220 may be distributed among multiplecommunication devices. Processing system 2230 may comprise amicroprocessor, microcontroller, logic circuit, or other processingdevice. Processing system 2230 may be distributed among multipleprocessing devices. User interface 2260 may comprise a keyboard, mouse,voice recognition interface, microphone and speakers, graphical display,touch screen, or other type of user interface device. User interface2260 may be distributed among multiple interface devices. Storage system2240 may comprise a disk, tape, integrated circuit, RAM, ROM, EEPROM,flash memory, network storage, server, or other memory function. Storagesystem 2240 may include computer readable medium. Storage system 2240may be distributed among multiple memory devices.

Processing system 2230 retrieves and executes software 2250 from storagesystem 2240. Processing system 2230 may retrieve and store data 2270.Processing system 2230 may also retrieve and store data viacommunication interface 2220. Processing system 2250 may create ormodify software 2250 or data 2270 to achieve a tangible result.Processing system may control communication interface 2220 or userinterface 2260 to achieve a tangible result. Processing system 2230 mayretrieve and execute remotely stored software via communicationinterface 2220.

Software 2250 and remotely stored software may comprise an operatingsystem, utilities, drivers, networking software, and other softwaretypically executed by a computer system. Software 2250 may comprise anapplication program, applet, firmware, or other form of machine-readableprocessing instructions typically executed by a computer system. Whenexecuted by processing system 2230, software 2250 or remotely storedsoftware may direct computer system 2200 to operate as described herein.

In an embodiment, a method of operating a communication system,includes: configuring a wireless interface radio to communicate with anaccess node using a first frequency band and a first series of timeallocations; configuring the wireless interface radio to communicatewith at least one client device using a second frequency band and asecond series of time allocations, the first series of time allocationsand the second series of time allocations to be non-overlapping; and,sending, via the second frequency band and to at least one clientdevice, information to be used by the at least one client device toselect a time to transmit using the second frequency band; and, based ona transmission received via the wireless interface radio, altering afirst duration of a first time allocation of at least one of the firstseries of time allocations and the second series of time allocations.

The transmission may be received using the first frequency band. Thefirst time allocation may be from the first series of time allocations.The first duration of the first time allocation may be increased inresponse to the transmission received using the first frequency band. Asecond duration of a second time allocation from the second series oftime allocations may be decreased in response to the transmissionreceived using the first frequency band.

The transmission may be received using the second frequency band wherethe first time allocation is from the second series of time allocations,and the duration of the first time allocation is increased in responseto the transmission received using the second frequency band. A secondduration of a second time allocation from the first series of timeallocations may be decreased in response to the transmission receivedusing the second frequency band.

In an embodiment, a method of operating a communication system,includes: configuring a high-throughput link that uses a wirelessinterface radio to communicate with an access node using a firstfrequency band and a first series of time allocations; configuring alow-latency link that uses the wireless interface radio to communicatewith at least one client device using a second frequency band and asecond series of time allocations, the first series of time allocationsand the second series of time allocations to be non-overlapping; and,sending, to a first client device communicating via the second frequencyband, a first time indicator, the first client device to, in response tothe first time indicator, select a first time to transmit that is duringa one of the second series of time allocations. The first time indicatormay correspond to a time that is referenced with respect to a boundarybetween time allocations of the first series of time allocations and thesecond series of time allocations.

This method may also include sending, to a second client devicecommunicating via the second frequency band, a second time indicator,the second client device to, in response to the second time indicator,select a second time to transmit that is during a one of the secondseries of time allocations and does not collide with the first time totransmit selected by the first client device.

This method may also include altering, based on a transmission receivedfrom the first client device, a first duration of a first timeallocation of at least one of the first series of time allocations andthe second series of time allocations. In response to the transmissionreceived from the first client device, the first duration may beincreased by a first amount. In response to the transmission receivedfrom the first client device, a second time allocation of following thefirst time allocation may be decreased by the first amount. The secondtime allocation may belong to the second series of time allocations.

In an embodiment a wireless capable device comprises a wirelessinterface radio to communicate with a first device using a firstfrequency band and a first series of time allocations. This firstfrequency band and first series of time allocations are to be used as ahigh-throughput link. The wireless interface radio is to alsocommunicate with at least a second device using a second frequency bandand a second series of time allocations. This second frequency band andsecond series of time allocations to be used as a low-latency link. Thefirst series of time allocations and the second series of timeallocations are to be non-overlapping. The wireless capable device alsocomprises a wireless interface layer control circuit to control thewireless interface radio. The wireless interface layer control circuitis to control the wireless interface radio to send, to the second devicecommunicating via the second frequency band, a first time indicator. Thesecond device is to, in response to the first time indicator, select afirst time to transmit that is during a one of the second series of timeallocations.

The first device may be an access node. The second device may be aclient device. The first time indicator may correspond to a time that isreferenced with respect to a boundary between time allocations of thefirst series of time allocations and the second series of timeallocations. The wireless interface layer control circuit may alsocontrol the wireless interface radio to send, to a third devicecommunicating via the second frequency band, a second time indicator.The second client device is to, in response to the second timeindicator, select a second time to transmit that is during a one of thesecond series of time allocations and does not collide with the firsttime to transmit selected by the second device.

Based on a transmission received from the second device, the wirelessdevice may alter a first duration of a first time allocation of at leastone of the first series of time allocations and the second series oftime allocations. In response to the transmission received from thesecond device, the wireless device may increase the first duration by afirst amount. In response to the transmission received from the seconddevice, the wireless device may decrease a second time allocation thatfollows the first time allocation by the first amount. The second timeallocation may belong to the second series of time allocations.

In an embodiment, a method of operating a client device includes:configuring a low-latency link between the client device and an accesspoint, the low-latency link to use a first frequency band and a firstseries of time allocations, the access point to communicate with anetwork access node using a second frequency band and a second series oftime allocations, the first series of time allocations and the secondseries of time allocations to be non-overlapping; receiving, from theaccess point and via the low-latency link, a first time indicator; and,in response to the time indicator, configuring the client device toselect a first selected transmit time that is during a first one of thefirst series of time allocations. The first time indicator maycorrespond to a time that is referenced with respect to a boundarybetween time allocations of the first series of time allocations and thesecond series of time allocations.

This method may also include sending, to a second client devicecommunicating via the second frequency band, a second time indicator,the second client device to, in response to the second time indicator,select a second time to transmit that is during a one of the secondseries of time allocations and does not collide with the first time totransmit selected by the first client device.

This method may also include, altering, based on a transmission receivedfrom the first client device, a first duration of a first timeallocation of at least one of the first series of time allocations andthe second series of time allocations. In response to the transmissionreceived from the first client device, the first duration may beincreased by a first amount. In response to the transmission receivedfrom the first client device, a second time allocation following thefirst time allocation may be decreased by the first amount. The secondtime allocation may belong to the second series of time allocations.

In an embodiment, a method of operating a client device includesconfiguring a low-latency link between the client device and a wirelessinterface of a computing device, the low-latency link to use a firstfrequency band and a first series of time allocations, the wirelessinterface to communicate with a network access node using a secondfrequency band and a second series of time allocations, the first seriesof time allocations and the second series of time allocations to benon-overlapping; receiving, from the wireless interface and via thelow-latency link, a first time indicator; and, in response to the timeindicator, configuring the client device to select a first selectedtransmit time that is during a first one of the first series of timeallocations.

This method may also include detecting that another device istransmitting at the first selected transmit time; and, in response todetecting that another device is transmitting at the selected transmittime, selecting a second transmit time. The second transmit time may beselected according to a wireless standard specified collision avoidancealgorithm performed by the client device. The second transmit time maybe selected to be during the first one of the first series of timeallocations. The second transmit time may be selected to be during asecond one of the first series of time allocations. The first timeindicator may correspond to a time that is referenced with respect to aboundary between time allocations of the first series of timeallocations and the second series of time allocations.

In an embodiment, a method of operating a communication system,includes: establishing a first wireless interface link to communicatewith an access node using a first channel of a frequency band;establishing a second wireless interface link to communicate with aclient device using a second channel of the frequency band; sending, viathe first wireless interface link, a first message to the access nodeindicating the first wireless interface link is to enter a first dormantstate; and, concurrently receiving data from the access node using thefirst channel and the client device using the second channel bydemodulating a wide channel comprising the first channel and the secondchannel, the concurrently received data including an indicator that theaccess node has received the first message indicating the first wirelessinterface link is to enter the first dormant state. The indicator thatthe access node has received the first message may be received via thefirst channel. The concurrently received data may include a secondindicator that the client device has exited a second dormant state wherethis second indicator is received via the second channel.

The concurrently received data may include an indicator that the clientdevice has exited a second dormant state. The indicator that the clientdevice has exited the second dormant state may be received via the firstchannel. The indicator that the client device has exited the seconddormant state may be received via the second channel.

This method may also include concurrently sending a second message tothe access node and a third message to the client device, the secondmessage being sent using the first channel and the third message beingsent using the second channel, the first message indicating to theaccess point that the first message is to keep the first channel busyfor an indicated period of time, the second message to be sent to theclient device using the second channel during the indicated period oftime. The concurrently received data may include an indicator that theclient device is requesting to communicate via the second link, and thethird message is a response to the request to communicate via the secondlink.

In an embodiment, a method of operating a client device, including:configuring a low-latency link between the client device and a softaccess point device, the low-latency link to use a first frequency bandand a first series of time allocations, the soft access point device toalso communicate with a network access node using a second frequencyband and a second series of time allocations, the first series of timeallocations and the second series of time allocations to benon-overlapping; transmitting, via the low-latency link, a first messageto the soft access point using the first frequency band during a firstone of the first series of time allocations; in response to notreceiving, via the first frequency band, a first acknowledgementassociated with the first message, sending a first retry of the firstmessage to the soft access point using the second frequency band duringthe first one of the first series of time allocations; and, in responseto receiving, via the second frequency band, a second acknowledgmentassociated with the first retry of the first message, sending a secondmessage to the soft access point using the second frequency band duringthe first one the first series of time allocations.

This method may also: send, in response to not receiving the secondacknowledgement associated with the retry of the first message, a secondretry of the first message to the soft access point using the firstfrequency band during the first one of the first series of timeallocations; and, in response to receiving, via the first frequencyband, a second acknowledgment associated with the second retry of thefirst message, send a third message to the soft access point using thefirst frequency band during the first one of the first series of timeallocations.

In an embodiment, a method of operating a communication system,including: configuring a wireless interface radio to communicate with afirst access node using a first frequency band and a first series oftime allocations; configuring the wireless interface radio tocommunicate with at least one client device using a second frequencyband and a second series of time allocations, the first series of timeallocations and the second series of time allocations to benon-overlapping; establishing, with the access node, a first wirelesscommunication link associated with first media access control (MAC)identifier; establishing, with the access node, a second wirelesscommunication link associated with a second MAC identifier; and,transmitting information, associated with the second MAC identifier, toconstrain a timing that the access node will schedule at least onetransmission by the access node.

The transmitted information associated with the second MAC identifiercan prevent a transmission by the access node that would start during aone of second series of time allocations but not end before an end ofthe one of the second series of time allocations. The transmittedinformation may constrain the timing that the access node schedules abroadcast frame. The transmitted information may constrain the timingthat the access node schedules a multicast frame. The transmittedinformation associated with the third MAC identifier can prevent atransmission by the access node during a period of time that thewireless interface radio is to communicate with at least one clientdevice using the second frequency band.

This method may also transmit information, associated with a third MACidentifier, to constrain a timing that the access node will schedule atleast one transmission by the access node, where the second MACidentifier is not associated with a wireless communication link with theaccess node.

This method may also receive, from a client device and via the firstfrequency band and during a one of the second series of timeallocations, a retry of a first message that was previously sent by theclient device using the second frequency band during the one of thesecond series of time allocations. This method may also transmit, to theclient device and via the first frequency band and during the one of thesecond series of time allocations, a response to the retry of the firstmessage.

In an embodiment, a wireless capable device comprises a wirelessinterface radio to communicate with an access node using a firstfrequency band and a first series of time allocations. The firstfrequency band and first series of time allocations are to be used as ahigh-throughput link. The wireless interface radio is to alsocommunicate with at least one client device using a second frequencyband and a second series of time allocations. The second frequency bandand a second series of time allocations are to be used as a low-latencylink. The first series of time allocations and the second series of timeallocations are to be non-overlapping. The wireless capable device alsocomprises a wireless interface layer control circuit to establish, withthe access node, a first wireless communication link associated withfirst media access control (MAC) identifier. The wireless interfacelayer control circuit to also establish, with the access node, a secondwireless communication link associated with a second MAC identifier. Thewireless interface radio to also transmit information associated withthe second MAC identifier to constrain a timing that the access nodewill schedule at least one transmission by the access node.

The transmitted information associated with the second MAC identifiermay prevent a transmission by the access node that would start during aone of second series of time allocations, but not end before an end ofthe one of the second series of time allocations. The transmittedinformation associated with the second MAC identifier may constrain thetiming that the access node schedules a broadcast frame. The transmittedinformation associated with the second MAC identifier may constrain thetiming that the access node schedules a multicast frame.

The wireless interface radio may also transmit information associatedwith a third MAC identifier to constrain a timing that the access nodewill schedule at least one transmission by the access node where thesecond MAC identifier is not associated with a wireless communicationlink with the access node. The transmitted information associated withthe third MAC identifier may prevent a transmission by the access nodeduring a period of time that the wireless interface radio is tocommunicate with at least one client device using the second frequencyband. The wireless interface radio may also receive, from a clientdevice and via the first frequency band and during a one of the secondseries of time allocations, a retry of a first message that waspreviously sent by the client device using the second frequency bandduring the one of the second series of time allocations. The wirelessinterface radio may also transmit, to the client device and via thefirst frequency band and during the one of the second series of timeallocations, a response to the retry of the first message.

In an embodiment, a method of operating a communication system,includes: configuring a wireless interface radio to communicate with afirst access node using a first frequency band and a first series oftime allocations; configuring the wireless interface radio tocommunicate with at least one client device using a second frequencyband and a second series of time allocations, the first series of timeallocations and the second series of time allocations to benon-overlapping; establishing, with the access node, a first wirelesscommunication link associated with first media access control (MAC)identifier; and, transmitting information, associated with a second MACidentifier, to constrain a timing that the access node will schedule atleast one transmission by the access node, the second MAC identifier notassociated with a wireless communication link with the access node.

The transmitted information associated with the second MAC identifiercan prevent a transmission by the access node during a period of timethat the wireless interface radio is to communicate with at least oneclient device using the second frequency band. The transmittedinformation may constrain the timing that the access node schedules abroadcast frame. The transmitted information may constrain the timingthat the access node schedules a multicast frame.

This method may also receive, from a client device and via the firstfrequency band and during a one of the second series of timeallocations, a retry of a first message that was previously sent by theclient device using the second frequency band during the one of thesecond series of time allocations. This method may also transmit, to theclient device and via the first frequency band and during the one of thesecond series of time allocations, a response to the retry of the firstmessage.

Although the subject matter has been described in language specific tostructural features and/or acts, it is to be understood that the subjectmatter defined in the appended claims is not necessarily limited to thespecific features or acts described above. Rather, the specific featuresand acts described above are disclosed as examples of implementing theclaims and other equivalent features and acts are intended to be withinthe scope of the claims.

What is claimed is:
 1. A wireless capable device, comprising: a wirelessinterface radio configured to communicate with a first device using afirst frequency band and a first series of time allocations, thewireless interface radio configured to also communicate with at least asecond device using a second frequency band and a second series of time,the first series of time allocations and the second series of timeallocations to be non-overlapping; a wireless interface layer controlcircuit configured to establish, with the first device, a first wirelesscommunication link associated with a first media access control (MAC)identifier and configured to establish, with the first device, a secondwireless communication link associated with a second MAC identifier thatappears, to the first device, to identify a different device than thefirst MAC identifier; and wherein the wireless interface radio isconfigured to also transmit information identified as coming from thesecond MAC identifier to prevent the first device from sending atransmission during a second time allocation in which the wirelessinterface radio communicates with the second device using the secondfrequency band.
 2. The wireless capable device of claim 1, wherein thefirst device comprises an access node and the second device comprises aclient device.
 3. The wireless capable device of claim 1, wherein theinformation identified as coming from the second MAC identifier preventsthe transmission by the first device that would start during the secondtime allocation but not end before an end of the second time allocation.4. The wireless capable device of claim 1, wherein the informationidentified as coming from the second MAC identifier is configured toconstrain a timing that the first device schedules a broadcast frame. 5.The wireless capable device of claim 1, wherein the informationidentified as coming from the second MAC identifier is configured toconstrain a timing that the first device schedules a multicast frame. 6.The wireless capable device of claim 1, wherein the wireless interfaceradio is configured to also transmit information identified as comingfrom a third MAC identifier that is not associated with a wirelesscommunication link with the first device.
 7. The wireless capable deviceof claim 6, wherein the information identified as coming from the thirdMAC identifier is configured to prevent a transmission by the firstdevice during a period of time that the wireless interface radio isconfigured to communicate with at least one device using the secondfrequency band.
 8. A method of operating a communication system,comprising: configuring a wireless interface radio to communicate withan access node using a first frequency band and a first series of timeallocations; configuring the wireless interface radio to communicatewith at least one client device using a second frequency band and asecond series of time allocations, the first series of time allocationsand the second series of time allocations to be non-overlapping;establishing, with the access node, a first wireless communication linkassociated with first media access control (MAC) identifier;transmitting, via the first wireless communication link, a message tothe access node that specifies an acknowledgement of the message by theaccess node; and, in response to not receiving the acknowledgement ofthe message before a predetermined time, transmitting information usingthe first frequency band, identified as coming from a second MACidentifier that appears, to the access node, to identify a differentdevice than the first MAC identifier, to prevent the access node fromsending a transmission during a second time allocation in which thewireless interface radio communicates with the at least one clientdevice using the second frequency band.
 9. The method of claim 8,wherein the information is configured to constrain a timing that theaccess node schedules a broadcast frame.
 10. The method of claim 8,wherein the information is configured to constrain a timing that theaccess node schedules a multicast frame.
 11. The method of claim 8,further comprising: receiving from a client device and via the firstfrequency band and during a time allocation of the second series of timeallocations, a retry of a first message that was previously sent by theclient device using the second frequency band during the time allocationof the second series of time allocations; and, transmitting, to theclient device and via the first frequency band and during the timeallocation of the second series of time allocations, a response to theretry of the first message.